The present invention concerns a plug-in coupling for systems involving pressurized media, where the coupling consists of two parts, and more particularly of one housing part and one connector part. The connector part can be inserted into a receiving opening of the housing part, while it is being sealed, and when it is in a plugged-in assembled condition, it can be locked in place and prevented from being released by means of a locking device. The locking device includes a retaining element, which is supported on one side of one of the coupling parts, and, while in the assembled state, engages a retaining groove of the other coupling part by means of a form-fit or a form-and-friction-fit. A release device is provided in such a manner that, starting from the assembled state, the retaining element is brought into a release position by means of a further insertion of the connector part, in which position the retaining groove is released, and it is maintained in this position in such a manner that the connector part can be removed from the receiving opening.
Such a coupling is known from the WO-A-96/35906 or the parallel SE-C-503 937. Here the locking device includes several individual locking parts as a retaining element, which are distributed along the circumference and are located inside an inner circular groove of the housing or the bushing part (female connector), respectively, in such a manner, that they are always at an angle to the direction of insertion and tilted radially toward the inside and thus collectively generate a practically conical shape. In the region of the radially interior ends, the locking parts are surrounded by an elastic ring (O-ring), which ensures that the locking parts only engage a circular groove of the connector part with their radially interior "locking ends", in order to lock the connector in place and keep it from loosening. In order to facilitate a subsequent release, a ring is located inside the circular groove of the connector part, which has a radial thickness corresponding to the depth of the circular groove. Viewed from an axial direction, this ring has a length that is smaller than the width of the groove, so that it can be disposed inside the retaining groove in a manner allowing it to be shifted back and forth. Because of this ring it is possible to spread the locking parts outwardly by means of a further insertion movement of the connector; subsequently, they are caused to have their locking ends superimposed upon the ring. Subsequently, a release of the connector is, therefore, possible, because the locking parts are kept spread apart by the ring when the connector is pulled out. This known coupling is relatively complicated and expensive with respect to its design and its ability to be manufactured, because it consists of quite a number of individual parts. Above all, the individual locking parts, as compared with the elastic O-ring, require a special process for their assembly as well as a special assembly device (feeding head), by means of which the individual locking parts are inserted and held in place for such a time period until they practically hold each other in place.
Other types of plug-in couplings are sufficiently known from many publications; the GB-A-799 155 and the EP-B-O005 865 are mentioned here merely as examples. In the first-mentioned publication a coupling is described, where an elastic retaining ring is pre-installed in an outer circular groove at the connector part as a retaining element. Subsequently, the retaining ring, in the assembled condition and after the connector part has been inserted, engages an interior groove in the housing part. Here, a subsequent release of the plug-in coupling is no longer possible, because the retaining ring is not accessible from the outside, and, therefore, cannot be unlocked. The second publication mentioned above describes several embodiments of plug-in couplings, where an elastic retaining ring inside the housing part is supported in an annular chamber, and after it is inserted, it engages the groove of the outer ring of the connector, and in fact, it does so with its total thickness as measured in the axial insertion direction, so that a genuine form-fit is achieved. Because here the annular chamber receiving the retaining ring is generated between a housing part and a threaded part, which is connected to it in a manner that allows it to be released, a release is possible for this known coupling by removing the threaded part, and then removing the connector along with the retaining ring, which had been in engagement with the circular groove.
In the last described kind of couplings, the retaining element, which consists of one part and is radially elastic, can, of course, be assembled more simply and more quickly than would be possible with the multiplicity of locking parts in accordance with the first mentioned publication, which establishes its own particular type, according to which, however, the release of the connector part is simpler and more convenient.
The present invention is thus based on the task of creating a plug-in coupling, where the connector part can be released by especially simple and economical means with respect to its design and manufacturing or its assembly, and where a release of the connector part is possible in a simple and rapid manner with respect to its operation.
According to the invention, this is achieved in that the release device contains a sleeve-like locking bar for use with the retaining groove, which locking bar is located on the side of the connector part containing the retaining groove, and which is arranged in such a manner that it is relatively moveable, and which can be actuated by moving the connector part, where the locking bar is provided in such a manner, that the retaining element, when it is in the release position, is superimposed radially on a circumferential area of the locking bar, and is thus held in the release position, and when the movement to remove the connector takes place, it is moved into the region of the retaining groove in such a manner, that a radial engagement of the retaining element with the retaining groove is impossible. Thus, the retaining groove according to the invention can be completely closed off by an axial displacement of the locking bar, or it can be completely, i.e. across the entire axial width of the groove, opened. Therefore, it is advantageous that a retaining element can be used, especially one which is made of one piece and has radial elasticity, and which, in the assembled position, is engaged by the retaining groove along practically its entire length as measured in the axial direction, or its thickness, respectively, and where the axial thickness of the retaining element is about equal to or slightly smaller than the axial length or the width, respectively, of the retaining groove.
In order to release the connector part, the locking bar (according to the invention) of the release device can be actuated in a very convenient manner by movement of the connector part alone, which when compared to the disassembly of a threaded insert, can, of course, be accomplished very much more simply and quickly, especially so because no tool will be required any more. The release device according to the invention thus at first sees to it that the retaining element is unlocked, and after that, a renewed engagement of the retaining element in the retaining groove during a release movement is impossible.
In a preferred embodiment of the invention, it is initially contemplated that in order to unlock the retaining element, the retaining groove be bounded on one side by an inclined surface (conical surface) in such a manner, that by the continued insertion of the connector part the retaining element is plastically deformed by way of the inclined surface and thus brought into the release position. In order to avoid at this point, that during the subsequent release movement of the connector part (during which, of course, the retaining element must again pass by the retaining groove), the retaining element is engaged again by the retaining groove, the retaining element is superimposed on the locking bar, which is guided so as to be relatively moveable, so that the retaining element is held in the release position. During the movement of the withdrawal of the connector part, the locking bar is then displaced by way of the retaining member, which is connected to the locking bar at least by means of a friction-fit, but preferably by a friction- and form-fit, in such a manner, that the retaining groove is covered or closed-off to keep it from being engaged by the retaining element. In this way, the plug-in coupling can now be removed without hindrance.
If subsequently the connector part is to be inserted once again, the retaining groove will now be automatically opened again, because a relative rearward movement of the locking bar from the region of the retaining groove takes place. As far as the design is concerned, this is accomplished by means of a radial protrusion of the locking bar, whereby the retaining element, during the insertion, is moved into an axial contact with the front surface of the locking bar, and it is thus moved away with respect to the retaining groove. The locking bar is thus practically something "which can be actuated by a connector".
By virtue of the invention, it can be advantageously avoided to construct the housing part in two pieces, because in order to release it, no housing parts need to be disassembled any longer. However, for a simple assembly of the individual parts, which are essential for its correct operation, the housing part can continue to be constructed in two pieces, and in this case it is useful if it consists of a base part and a closure part, which is connected with it in such a way that it can be detached. The design of the closure part, however, is completely arbitrary. For example, it could consist of a male pipe fitting (in accordance with the initially mentioned EP-P-O 005 865). An essentially hollow cylindrical insert part may also be contemplated, which may be connected to the base part by other connecting means as an alternative to a screw coupling, for example, by a bayonet connection and/or a snap-in connection. Beyond this, a lid-like closure part, for example in the form of a flat closure plate, is possible (For a comparison see, for example, DE 39 25 293 C2). In every case, the important thing is only to limit a receiving chamber or the retaining groove, respectively, for the retaining element in an axial direction, so that a simple assembly and disassembly of the individual parts is possible. In this context, even a closure plate, for example, can be connected movably to the base part in such a manner, that, in a first position, the individual parts can be assembled or disassembled through a sufficiently large opening, and, in a second position, the opening can then be accordingly made smaller in such a way, that only the connector part can be plugged in or removed. Such an embodiment is known as such, for example, from the DE 38 10 385 A1.
In conjunction with the invention, i.e. in combination with the release device according to the invention, it is of particular advantage, if the retaining element consists of at least two individual elements, which when viewed in the direction of their insertion, are located one behind the other in such a manner, that during the insertion or the removal process, respectively, the individual elements are always deformed radially, one after the other, or they successively engage the retaining groove, one after the other. Preferably, the individual elements are fashioned in the form of lamella, as clamps, which can be elastically deformed in a radial direction, or as spring washers, in which case preferably two to six, especially five equally lamella-shaped individual elements are placed next to each other like a package. By means of this advantageous embodiment it is achieved, that for the actuation of the retaining element, i.e. for its radial elastic deformation, only a relatively small insertion force is required, whereas in the assembled position a very high holding force for the ability to sustain the interior system pressures is ensured. Details of this preferred embodiment are also contained in a separate EP-application of the same priority on the basis of the German patent application with the file number DE 197 07 372; this application will be fully referred to.
Further advantageous characteristics of the embodiments of the invention are contained in the dependent claims as well as in the subsequent description.
On the basis of the examples of the preferred embodiments and the designs illustrated in the drawings, the invention will now be described in more detail. The illustrations show the following: